1. Field of the Invention
The present invention pertains to a device for the handling of chips for semi-conductor devices, such as diodes or transistors, so that these chips can be presented at a precise location where they are taken up by a pipette to be fixed to a socket by an automatic assembly line.
2. Description of the Prior Art
At present, in the semi-conductor industry, it is still necessary to manipulate bare chips so that they can be fixed on a support with connections giving access to the electrical function, and often also comprising a protective cover. The support may be the socket of a diode package or transistor package of the TO 39 type, the grid of an integrated circuit package (DIL type), or the substrate of a hybrid circuit.
There are means and method which are very appropriate as long as the chips to be handled have dimensions greater than approximately 1 mm square. For example, in one prior art method, a slice of semi-conducting material, out of which the devices have been made, is laid on a plastic tape. After being cut out by laser or with a cutting diamond, the sheet of plastic matter is stretched. At this point, the chips are presented in order and spaced out so that they can be taken up with a suction pipette.
However, this is not the case with very small chips, ranging from 0.25 mm square to 0.4-0.5 mm square, corresponding to diodes or ultra-high frequency transistors (where it is known that the sizes become smaller as the frequency becomes higher. The diodes may also be optoelectronic diodes, of the electroluminescent or laser type. To cut out the layer of semi-conducting material into chips with such small sizes and such low weights, the slice has to be bonded to a base (for example, a copper plate). The chips are then unbonded and cleaned of bonder, and, at that moment, they are in a loose state.